Problem: 6 folders cost $8.76. Which equation would help determine the cost of 2 folders?
Answer: There are several equations that could help determine the cost, each with a slightly different approach. We know the cost of 6 folders. We want to know the cost of 2 folders. We can write the numbers of folders as a proportion: $\dfrac{6}{2}$ We know 6 folders costs $8.76. We can let $x$ represent the unknown cost of 2 folders. The proportion of these costs can be expressed as: $\dfrac{\$8.76}{x}$ The cost changes along with the number of folders purchased, and so the two proportions are equivalent. $\dfrac{6}{2} = \dfrac{\$8.76}{x}$